The present invention relates to the discovery, identification, and characterization of novel human polynucleotide sequences and the novel polypeptides encoded thereby. The invention encompasses the described polynucleotides, host cell expression systems, the encoded proteins or polypeptides, and fusion proteins and peptides derived therefrom, antibodies to the encoded proteins or peptides, and genetically engineered animals that lack functional forms of the genes encoding the disclosed sequences, over express the disclosed sequences, as well as antagonists and agonists of the proteins, along with other compounds that modulate the expression or activity of the proteins encoded by the disclosed sequences that can be used for diagnosis, drug screening, clinical trial monitoring, the treatment of physiological or behavioral disorders, or otherwise improving the quality of life.
Uncoupling proteins (UCPs) are found in the mitochondria, but are encoded within the nucleus. In the mitochondria, UCPs uncouple, or regulate, the gradient that drives energy production in the cell/body. As such, UCPs effectively modulate the efficiency of energy production in the body, and hence body metabolism. Given the role of UCPs in the body, they are thought to be important targets for the study of thermogenesis, obesity, cachexia, and other metabolically related physiological functions, diseases, and disorders.
The present invention relates to the discovery, identification, and characterization of nucleotides that encode novel human UCPs, and the corresponding amino acid sequences encoded by the disclosed sequences. The novel human uncoupling proteins (NUCPs) described for the first time herein share structural relatedness with other mammalian uncoupling proteins and brain mitochondrial carrier proteins. The novel human nucleic acid sequences described herein encode proteins of 291 and 293 amino acids in length (see SEQ ID NOS:2 and 4).
A murine homologue of the described NUCPs has been identified and a xe2x80x9cknockoutxe2x80x9d ES cell line has been produced using the methods described in U.S. application Ser. No. 08/942,806, herein incorporated by reference. Alternatively, such knockout cells and animals can be produced using conventional methods for generating genetically engineered animals and cells(see, for example, PCT Applic. No. PCT/US98/03243, filed Feb. 20, 1998, herein incorporated by reference). Accordingly, an additional aspect of the present invention includes knockout cells and animals having genetically engineered mutations in gene encoding the presently described NUCPs.
The invention encompasses the nucleotides presented in the Sequence Listing, host cells expressing such nucleotides, and the expression products of such nucleotides, and: (a) nucleotides that encode mammalian homologs of the described genes, including the specifically described NUCPs, and the NUCP products; (b) nucleotides that encode one or more portions of the NUCPs that correspond to functional domains, and the polypeptide products specified by such nucleotide sequences, including but not limited to the novel regions of any active domain(s); (c) isolated nucleotides that encode mutant versions, engineered or naturally occurring, of the described NUCPs in which all or a part of at least one domain is deleted or altered, and the polypeptide products specified by such nucleotide sequences, including but not limited to soluble proteins and peptides in which all or a portion of the signal sequence in deleted; (d) nucleotides that encode chimeric fusion proteins containing all or a portion of a coding region of NUCP, or one of its domains (e.g., a transmembrane domain, accessory protein/self-association domain, etc.) fused to another peptide or polypeptide.
The invention also encompasses agonists and antagonists of NUCPs, including small molecules, large molecules, mutant NUCPs, or portions thereof that compete with or bind to native NUCPs, antibodies, and nucleotide sequences that can be used to inhibit the expression of the described NUCPs (e.g., antisense, ribozyme molecules, and gene or regulatory sequence replacement constructs) or to enhance the expression of the described NUCPs (e.g., expression constructs that place the described genes under the control of a strong promoter system), as well as transgenic animals that express a NUCP transgene, or xe2x80x9cknockoutsxe2x80x9d (which can be conditional) that do not express functional NUCP.
Further, the present invention also relates to methods for using of the described NUCP products for the identification of compounds that modulate, i.e., act as agonists or antagonists, of NUCP expression and/or NUCP product activity. Such compounds can be used as therapeutic agents for the treatment of any of a wide variety of symptomatic representations of biological disorders or imbalances.
An additional embodiment of the present invention includes therapy and treatments mediated by NUCP gene delivery. Gene delivery can be to somatic or stem cells, and may be effected using viral (i.e., retrovirus, adeno-associated virus, etc.) or non-viral (i.e., cationic lipids, formulations using xe2x80x9cnakedxe2x80x9d DNA, etc.) methods.
The Sequence Listing provides the sequences of the NUCP polynucleotides, and the amino acid sequences encoded thereby.